Luminance level control device

Abstract

A scene change detecting circuit (1) detects a scene change of video. An average luminance level operating circuit (2) calculates an average luminance level (APL) of a video signal (VD). A luminance overdrive amount calculating circuit (3) calculates a luminance overdrive amount (OD) based on the average luminance level (APL). A time-linked attenuating circuit (7) outputs a power consumption limit correction amount (PA) by attenuating the luminance overdrive amount (OD) with an elapse of time from a point in time of detecting the scene change. An adder (8) adds the power consumption limit correction amount (PA) and a reference power consumption limit value (Lp) to output the addition result as a power consumption limit amount (PL). An ABL circuit (4) calculates a luminance limit amount (BL) based on luminance limit characteristics, the average luminance level (APL) and the power consumption limit amount (PL). A luminance level control circuit (5) determines a display drive condition (BC) based on the luminance limit amount (BL). A PDP drive controller (6) drives a display panel (20) based on the video signal (VD) and the display driving condition (BC).

Description

TECHNICAL FIELD[0001]The present invention relates to a luminance level control device that controls a luminance level of video to be displayed on a display panel.BACKGROUND ART[0002]A plasma display panel includes a plurality of discharge cells arranged in the form of a matrix. In this plasma display panel, gas discharges are induced in the selected discharge cells, generating ultraviolet rays. The ultraviolet rays cause phosphors in the discharge cells to be excited, so that the discharge cells emit light. The number of times of discharges in the discharge cells per unit time, that is, the number of discharge sustain pulses applied to the discharge cells is controlled, thereby enabling display of luminance in multiple levels of gray.[0003]Generally, a sub-field method is employed as a driving system of the plasma display panel. In the sub-field method, one field corresponding to one screen of video is temporally divided into a plurality of sub-fields, and the ratio of a light emis...

AI Technical Summary

Benefits of technology

[0060]According to the present invention, a viewer can clearly recognize a scene change because a luminance level of video increases at the time of the scene change. In addition, the luminance level of video attenuates with an elapse of time after the scene change, so that power consumption is reduced. Since the scene change of video is not very frequent in general video, average power consumption can be sufficiently reduced.

[0061]Luminance and power consumption are temporally dispersed, thus enabling both high luminance display and reduction in power consumption.

Problems solved by technology

However, since the ABL characteristics cause the luminance level of the displayed video to be immediately controlled every time the average peak level changes, it has a disadvantage in that unnatural changes in luminance are visually recognized.

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